Due to the increasing popularity of easy-care fabrics made of synthetic fibers as well as the ever increasing energy costs and growing ecological concerns of detergent users, the once popular warm and hot water washes have now taken a back seat to washing fabrics in cold water (30° C. and below). Many commercially available laundry detergents are even advertised as being suitable for washing fabrics at 15° C. or even 9° C. To achieve satisfactory washing results at such low temperatures, results comparable to those obtained with hot-water washes, the demands on low-temperature detergents are especially high.
It is known to include certain additives in detergent compositions to enhance the detergent power of conventional surfactants, so as to improve the removal of grease stains at temperatures of 30° C. and below. For example, laundry detergents containing an aliphatic amine compound, in addition to at least one synthetic anionic and/or nonionic surfactant, are known. Also, the use of linear, alkyl-modified (secondary) alkoxypropylamines in laundry detergents to improve cleaning at low temperatures is known. These known laundry detergents, however, are unable to achieve satisfactory cleaning at cold temperatures.
Furthermore, the use of linear, primary polyoxyalkyleneamines (e.g., Jeffamine® D-230) to stabilize fragrances in laundry detergents and provide longer lasting scent is also known. Also, the use of high-molecular-weight (molecular weight of at least about 1000), branched, trifunctional, primary amines (e.g., Jeffamine® T-5000 polyetheramine) to suppress suds in liquid detergents is known. Additionally, an etheramine mixture containing a monoether diamine (e.g., at least 10% by weight of the etheramine mixture), methods for its production, and its use as a curing agent or as a raw material in the synthesis of polymers are known. Finally, the use of compounds derived from the reaction of diamines or polyamines with alkylene oxides and compounds derived from the reaction of amine terminated polyethers with epoxide functional compounds to suppress suds is known.
There is a continuing need for a detergent additive that can improve cleaning performance at low wash temperatures, e.g., at 30° C. or even lower, without interfering with the production and the quality of the laundry detergents in any way. More specifically, there is a need for a detergent additive that can improve cold water grease cleaning, without adversely affecting particulate cleaning. Surprisingly, it has been found that the liquid laundry detergent compositions of the invention provide increased grease removal (particularly in cold water).